1. Field of the Invention
The present invention relates to an improvement in a distance measurement and photometry sensor device suitable for a lens shutter camera or the like.
2. Related Background Art
Heretofore, as for a device loaded with a photometry sensor and a distance measurement sensor for use in a lens shutter camera, there is a distance measurement and photometry sensor device disclosed in U.S. Pat. No. 5,302,997. A schematic planer layout of this distance measurement and photometry sensor device is shown in FIG. 7. Note that, the term distance measurement means to obtain distance information or defocus information, i.e., focal point adjustment information.
In the figure, a photometry sensor 30 includes a photometry center segment 32, photometry inner segments 34A to 34D, and photometry outer segments 36A to 36D. Line sensors 40 and 42 each includes a plurality of photodiodes (1 to n) constituting pixels. Distance measurement sensors are constituted by those line sensors 40 and 42, respectively. On a semiconductor substrate 50, the photometry sensor and a circuit portion for executing a signal processing for the photometry sensor, and the distance measurement sensors and circuit portions (each including amplifiers, noise removal circuits, maximum value detection circuits, signal output circuits, and registers) for executing a signal processing for the distance measurement sensors are mounted. Those constituent elements constitute the distance measurement and photometry sensor device. In addition, reference symbols H and W designate a height and a width of a photometry area, respectively, and reference symbol D designates a base length.
For the purpose of carrying out the distance measurement on the basis of the detection of a phase difference, two line sensors 40 and 42 are required for the above-mentioned distance measurement sensors. A certain distance, a so-called base length D of about several millimeters is required between the two line sensors 40 and 42. Thus, a space is present between the line sensors 40 and 42 in terms of layout. Consequently, the photometry sensor 30 is provided between the line sensors 40 and 42, whereby the two kinds of sensors are efficiently arranged on the semiconductor substrate 50.
In addition, there is proposed a sensor device in which imaging lenses for imaging a reflected light from a photographing screen on the distance measurement sensors (the line sensors 40 and 42), and the photometry sensor 30 are provided in correspondence to the distance measurement sensors, and the photometry sensor 30, respectively. Also, there is proposed a sensor device in which in order to make the projection positions on a subject coincide with each other, as shown in FIG. 7, centers of the distance measurement sensors and the photometry sensor are arranged so as to be coaxial (on a line designated with reference numeral 60) in a direction parallel with the base length direction.
However, in the above-mentioned prior art, the line sensors 40 and 42 as the constituent elements of the distance measurement sensors, and the photometry sensor 30 are arranged on the same plane as the semiconductor substrate 50, and the sensor centers of the line sensors 40 and 42, and the sensor center of the photometry sensor 30 are made to be coaxial in the direction parallel with the base length direction. As a result, the respective sizes of the semiconductor chip in the base length direction and in a direction perpendicular to the base length direction (in a vertical direction in FIG. 7) cannot be reduced so much.
More specifically, each of the line sensors is constituted by a plurality of photodiodes, and circuit portions (refer to FIG. 3 which will be described later) for executing a signal processing such as amplifiers, noise removal circuits, maximum value detection circuits, signal output circuits, and registers are required for the photodiodes. In FIG. 7, those circuit portions are arranged in a direction perpendicular to the base length direction of the line sensors (in order to efficiently utilize a space in the vertical direction). In addition, the sensor centers of the distance measurement line sensors, and the sensor center of the photometry sensor are made to be coaxial in the direction parallel with the base length direction. Thus, the circuit portions are arranged so as to form a line in the vertical direction with respect to the positions of the distance measurement line sensors and the photometry sensor. Consequently, there is encountered a problem that the respective sizes of the semiconductor chip, on which the distance measurement line sensors and the photometry sensor are formed, in the base length direction and in the vertical direction can not be reduced so much.